Beverage device for making a beverage with a foam layer on top

ABSTRACT

A beverage device for making a beverage with a foam layer on top includes a foaming device for generating foam from the beverage. The foaming device includes at least one inlet opening for receiving beverage under pressure and at least one outlet opening for the beverage with the foam. To obtain a fine and stable foam layer on the beverage, the foaming device generates a spray of beverage, and includes a collision surface which, in use, is hit by the beverage spray thus generating the foam.

This application is a continuation of U.S. patent application Ser.10/499,626, filed on 21 Jun. 2004, which is a national stage of PCTapplication PCT/IB02/05678 filed on 20 Dec. 2002, and claims priorityunder 35 U.S.C. §119 from European patent application 0120086.0 filed 24Dec. 2001, the entirety of each of which is hereby incorporated byreference in its entirety for all purposes as if fully set forth herein.

The invention relates to a beverage device for making a beverage with afoam layer on top, comprising foaming means for generating foam fromsaid beverage, said foaming means comprising at least one inlet openingfor receiving beverage under pressure and at least one outlet openingfor the beverage with the foam.

Such a device is known from European patent application 0 878 158. Inthis patent application, the device is a coffee apparatus, the foamingmeans comprises a buffer reservoir spaced from the inlet opening andpositioned such that, in use, a jet of coffee extract is squirted fromthe inlet passage into a surface of coffee extract already received inthe buffer reservoir. Coffee extract is fed to the inlet passage underrelatively low pressure, and the spout opening of the inlet generates ajet of coffee extract. This jet of coffee extract ends up in the bufferreservoir, so that the buffer reservoir will be filled with a quantityof coffee extract. Due to the fact that the jet of coffee extract issquirted into the liquid surface of the filled buffer reservoir, bubbleswill be formed in the buffer reservoir, so that a foam layer isgenerated. Although the foam generated in this way gives a satisfactoryresult, the reproducibility of the generated foam is not alwayssufficient, in particular as regards the size of the foam bubbles. Othercoffee makers for brewing coffee with a foam layer on top are thewell-known espresso coffee apparatuses. However, espresso coffee makersrequire a pressure of up to 12-15 bar overpressure, which is much higherthan in the coffee maker of the above described type, which requiresonly about 1.4 bar.

It is an object of the invention to provide a beverage device for makinga beverage with a fine and stable foam layer on the beverage.

According to the present invention, this object is achieved in that thefoaming means comprises means for generating a spray of beverage, andsaid foaming means further comprises a collision surface which, in use,is hit by said spray of beverage, thereby generating foam. A spray ofbeverage consists of a plurality of fine droplets that hit the collisionsurface. The impact of the droplets causes a generation of fine bubblesor foam, which foam together with the beverage flows towards the outletopening and can then be received in a cup or drinking glass. The resultis a beverage with a fine and stable foam layer on top.

To obtain a reliable and continuous spray, a preferred embodiment of thedevice comprises a whirl chamber having a central outlet opening forgenerating a conical spray of beverage. The rotating conical sprayincreases the impact of droplets on the collision surface and hence thegeneration of foam.

Further preferred embodiments and advantages of the invention are setforth in the dependent claims.

Further features, effects, and details of the invention are describedwith reference to the embodiment of a coffee maker shown in thedrawings.

FIG. 1 is a lateral cross-sectional view of a coffee maker comprising anexample of an apparatus according to the present invention;

FIG. 2 is an enlarged view of a coffee extracting unit of the coffeemaker according to FIG. 1,

FIG. 3 is an enlarged cross-sectional view of a bottom portion of thecoffee extracting unit shown in FIG. 2;

FIG. 3 a is an alternative example of the coffee extracting unit of FIG.3;

FIG. 3 b shows a wire mesh shaped collision surface;

FIG. 4 is an exploded view of the coffee extracting unit according toFIG. 2; and

FIG. 5 is a schematized representation in top plan view of the coffeeextract flow through a whirl chamber of the apparatus according to theinvention.

In FIG. 1, reference numeral 1 designates a coffee maker according tothe invention for preparing coffee extract having a small-bubble foamlayer.

The coffee maker 1 has a housing 2 and a cover 3 hinged to the housing 2by a hinge 4 and fixed in closed position by latches (not shown). Thehousing 2 has a forwardly extending portion of which a top surface 5forms a plateau for supporting one or more cups 6 to be filled withcoffee. Within the housing, a water reservoir 7 is located which is openat a top end 8 when the cover 3 is open and closed when the cover 3 isin the closed operating condition shown in FIG. 1. A conduit 9 extendsthrough a heating chamber 46 in which an electric heating element 47 isarranged. A pump 45 is arranged in the conduit 9 upstream of the heater47 for supplying water from the reservoir 7.

A sprinkling head 11 which is located in a top wall 12 of an extractingchamber 13 forms the end of the conduit 9. The top end of a tray andspout part 15, which is also shown separately in FIGS. 2 and 4, forms abottom 14 of the extracting chamber 13. The bottom 14 forms a tray withsupport stubs 16 and interspaces 17 facilitating coffee extract pressedout of a coffee pouch arranged on top of the bottom to flow into aninlet passage 18 downstream of the extracting chamber 13. In operatingcondition, the extracting chamber is hermetically sealed against waterso that no significant loss of pressure generated by the pump 45 occursand all or virtually all pressure generated by the pump 45 reaches theextracting chamber 13 when coffee is being extracted. It is observedthat, even though the extracting chamber according to the presentexample is adapted for receiving coffee pouches, a suitably fine mesh inthe bottom or use of coffee filters would in principle allow the use ofloose ground coffee.

The inlet passage 18 extends through a stub 19 that projects from thebottom 14. Near a bottom end, the inlet passage branches into twotwister branches of which upstream portions 20, 21 (see also FIG. 3)branch radially away from the main branch of the inlet channel and ofwhich downstream portions 22 extend in screw-like fashion about theoutside of the stub 19 and are also bound by the inner surface 23 of acup 24 which receives a bottom end of the stub 19 and is sealed againstthe stub by an O-ring 25 when in operating condition.

The inlet channel's 18 downstream branch portions 22 issue into a whirlchamber 26 between an end 27 of the stub 19 and the bottom 28 of the cup24. The cup 24 is detachably connected to the stub 19 by a bayonetclosure composed of notches 29, 30 engaging ribs 31, 32. That the cup 24is detachably connected to the stub 19 provides the advantage that thewhirl chamber 26 can be easily cleaned. The bayonet closure is quicklyconnectable and disconnectable but nevertheless forms a reliableconnection also when an operation axial pressure is applied to the cup24 due to the pressure at which coffee extract is supplied to the whirlchamber 26.

An outlet passage 33 extends from a central portion of the bottom 28 ofthe whirl chamber 26, and its outlet end faces a top surface 34 of abottom 35 of a lower housing 37 in which the bottom 14 of the extractingchamber 13, the stub 19, and the cup 24 are suspended. The outletpassage 33 is located at a small distance from the top surface 34, whichsurface acts as a collision surface 34 for coffee extract as will beexplained hereinafter.

The space 36 between the bottom 28 of the cup 24 and the bottom 35 ofthe lower housing 37 communicates with two dispensing passages 40, 41extending through dispensing spouts 38, 39 via which coffee extract canflow to the cups 6 on the platform 5.

For forming foam on coffee extract, the apparatus is provided with acoffee extract path extending from the extracting chamber 13, whichcoffee extract path is in this example formed by the inlet passage 18for receiving coffee extract, the whirl chamber 26 downstream of theinlet passage 18 for receiving coffee extract from the inlet passage 18,and the outlet passage 33 extending from the whirl chamber 26 fordischarging coffee extract from the whirl chamber 26. The configurationof the branches 20, 21 and 22 of the inlet passage causes the coffeeextract in the whirl chamber 26 to rotate during operating, and coffeeextract is discharged in a rotating condition from the whirl chamber 26via the outlet passage 33. The rotating coffee extract (see FIG. 5)causes a conical spray 48 when discharged through the outlet passage 33.The spray consists of a plurality of fine droplets which hit thecollision surface 34. The impact of the droplets causes a generation ofvery fine bubbles or foam. The coffee extract with the foam flows viaspace 36, dispensing channels 40,41, and spouts 38,39 into the cup(s) 6.The foam floating on the coffee extract thus provides the required“crema” effect on the coffee. A particular advantage of making coffeewith the “crema” effect in this way is that the required pressure cangenerally be lower than in a known apparatus in which the coffee extractis squirted into a buffer quantity of coffee extract in a bufferreservoir. Satisfactory results have been obtained, for example, atpressures of about 1 bar overpressure, whereas in the known apparatusgenerally about 1.4 bar is required to obtain a satisfactory “crema”.

It is particularly advantageous for obtaining an effective foamformation, that the apparatus is arranged for imparting the rotationabout an axis 42 (FIG. 3) and that the outlet passage 33 has an upstreamend coaxial with the axis 42. As is illustrated by FIG. 5, the rotatingcoffee extract forms a vortex and is discharged from a core of thevortex. The internal bottom surface of the whirl chamber 26 slopesinwardly downward to a central portion from where the outlet passage 33extends. It was been found that this feature is also advantageous forgenerating a conical spray 48 and thus for an effective foam formation,in particular if the bottom surface has a conical shape.

More in general, it is advantageous if the outlet passage 33 extendsfrom a lowermost portion of the inner bottom surface of the whirlchamber 26, because this ensures that all the coffee extract is drainedat the end of the preparation of each serving.

In the present example, the rotation is imparted to the coffee extractin the whirl chamber 26 in that the downstream portions 22 of thebranches of the inlet channel 18 issue into the whirl chamber 26 indirections having a directional component tangential to the central axis42 of the whirl chamber 26. In FIG. 5, arrows 43, 44 schematicallyindicate these directions. This is advantageous, because no separatemoveable parts are required and the impulse imparted to the coffeeextract in the chamber is proportional to the amount of coffee extractthat is being supplied to the chamber. However, the rotation may beimparted in numerous alternative manners, for example using externallydriven stirring blades, air, steam, and/or guide ribs in the inletpassage, which may, for example, extend helically with a pitch whichreduces in downstream direction.

Since more than one of the inlet passages 22 issue into the whirlchamber 26, and the tangential directional components of the directionsin which the inlet passages 22 issue into the chamber are oriented inaccordance with a common sense of rotation about the central axis 42,the feeding of coffee extract is distributed over several positions, andthe rotation is also imparted in several positions. This is advantageousfor evenly distributing coffee extract and motion circumferentially,especially if the positions where the inlet passages 22 issue into thewhirl chamber 26 are evenly distributed circumferentially about the axis42.

It was also been found that it is advantageous for obtaining aneffective foam formation if a wall portion 27 of the whirl chamber 26facing an upstream end of the outlet passage 33 is located at less than0.5 to 1.0 mm from the upstream end of the outlet passage.

Furthermore, for effective operation, the outlet passage 33 preferablyis a nozzle having a most restricted section 44 with a smallestcross-sectional surface and widening in downstream direction from themost restricted section 44, preferably at an average angle of 45° to 70°degrees to a central axis 42 of the outlet passage 33. The mostrestricted section 44 of the outlet passage 33 preferably has across-sectional surface area of less than 1 mm². This applies inparticular to apparatuses intended to prepare one or two cups of coffeeat a time at a pressure in the reservoir 7 or at the outlet passage 33of 0.8 to 1.2 bar. Good foaming results have been obtained when thedownstream end 45 of the outlet passage 33 faces the collision surface34 transverse to the outlet passage 33 at a distance of 3 to 7 mm.

In the present example, the proposed apparatus is integrated into acoffee maker for preparing coffee extract and, for this purpose,comprising the extracting chamber 13 for retaining ground coffee duringextraction of coffee extract, which extracting chamber communicates withthe inlet passage 18 and is located upstream thereof. However, it isalternatively possible to provide such apparatus as a separate devicefor foaming up coffee extract which has been prepared in an otherwiseconventional apparatus or which is supplied as instant coffee orconcentrated coffee extract. For this purpose, the inlet passage may beconnected, for example, to a pressure pump or a reservoir forpressurizing the coffee extract after it has left the extractingchamber. It will be clear that within the framework of the presentinvention many obvious and non-obvious modifications from the abovedescribed example other than the above-described variants are alsoconceivable.

In an alternative example shown in FIG. 3 a, the collision surface isformed by an inside wall 50 of a tube 49 which extends downward of theoutlet passage 33 and is coaxial with the central axis 42 of the outletpassage. The droplets of the conical spray 48 hit the inside wall 50 ofthe tube 49, thus generating fine bubbles or foam. The coffee extractwith the foam flows downward to the outlet 51 of the tube and from therefurther to the dispensing spouts 38,39. In FIG. 3 a, the inside wall ofthe tube is vertically orientated, i.e. parallel to the central axis 42.It is also possible to have a tapered tube with a tapering wall,preferably with the smallest dimension in the downstream direction. Inthis way the impact of the droplets for generating foam is moreeffective.

In another example shown in FIG. 3 b, the collision surface is formed bya wire mesh 52. The droplets hit the wires 53 of the mesh, thusgenerating foam. By hitting a wire, a droplet can be split into smallerdroplets which hit neighbouring wires. This causes an even finer foam.

Although the sprays described in the above examples are conical rotatingsprays, it will be clear that alternative shapes of sprays, such as astraight, parallel spray, may be used to generate a foam layer on top ofa beverage.

To integrate automated coffee making with the foam forming function, thecoffee maker described also comprises the water reservoir 7 and thewater supply conduit 9 communicating with the extracting chamber 13 forsupplying water from the reservoir 7 to the extracting chamber 13.

For generating the pressure required for the foam formation, the waterreservoir 7, the water supply conduit 9, the extraction chamber 13, theinlet passage 18 and the whirl chamber 26 form an hermetically sealedenclosure, allowing pressure in the enclosure to be discharged via theoutlet passage only at least to a significant extent and in theoperating condition.

1. A device for making a beverage with a foam layer on top, comprising:foaming means for generating foam from the beverage, the foaming meansincluding (i) at least one inlet opening for receiving beverage underpressure and at least one outlet opening for the beverage with the foam,(ii) means for generating a spray of beverage including a whirl chamberfor rotating the beverage to generate the spray, and (iii) a collisionsurface which, in use, is hit by the spray of beverage, therebygenerating foam, the collision surface being formed by a wire mesh. 2.The device of claim 1, wherein the spray of beverage has a conical shapeand a central axis, and wherein the collision surface extendssubstantially perpendicularly to the central axis of the conical sprayof beverage.
 3. The device of claim 1, wherein the foaming means iscomprised by an apparatus for making coffee having an extraction chamberfor filtering ground coffee by means of water under pressure forobtaining a coffee extract, the means for generating a spray of beverageproviding for generating a spray of coffee extract and being situateddownstream of the extraction chamber.
 4. A device for making a beveragewith a foam layer on top, comprising: foaming means for generating foamfrom the beverage, the foaming means including (i) at least one inletopening for receiving beverage under pressure and at least one outletopening for the beverage with the foam, (ii) means for generating aspray of beverage, and (iii) a collision surface which, in use, is hitby the spray of beverage, thereby generating foam, the collision surfacebeing formed by a wire mesh, wherein the means for generating the sprayof beverage includes a whirl chamber having a central outlet opening forgenerating a conical spray of beverage.
 5. The device of claim 4,wherein the whirl chamber has a conical shape narrowing toward thecentral outlet opening, the central outlet opening being located at thelowest part of the whirl chamber.
 6. The device of claim 4, furthercomprising a twister branch, the twister branch being disposed betweenthe inlet opening and the whirl chamber, the twister branch having anupstream portion and a downstream portion, the upstream portionbranching from the inlet opening so as to enable beverage flow from theinlet opening, and the downstream portion communicating with the whirlchamber so as to issue beverage into the whirl chamber in directionshaving a tangential component with respect to the axis of the whirlchamber.
 7. The device of claim 6, wherein the upstream portion of thetwister branch branches in a radial manner from the inlet opening.
 8. Adevice for making a beverage with a foam layer on top, comprising:foaming means for generating foam from the beverage, the foaming meansincluding (i) at least one inlet opening for receiving beverage underpressure and at least one outlet opening for the beverage with the foam,(ii) means for generating a spray of beverage, and (iii) a collisionsurface which, in use, is hit by the spray of beverage, therebygenerating foam, the collision surface being formed by an inside wall ofa tube which extends downward of the means for generating the spray ofbeverage and which tube is coaxial with a central axis of the spray ofbeverage.
 9. The device of claim 8, wherein the inside wall of the tubeextends in parallel to the central axis of the spray of beverage. 10.The device of claim 8, wherein the inside wall of the tube is tapered ina direction along the central axis of the spray of beverage, the insidewall tapering to a smaller diameter as it proceeds downstream withrespect to the spray of beverage.
 11. The device of claim 8, wherein thefoaming means is comprised by an apparatus for making coffee having anextraction chamber for filtering ground coffee by means of water underpressure for obtaining a coffee extract, the means for generating aspray of beverage providing for generating a spray of coffee extract andbeing situated downstream of the extraction chamber.
 12. The device ofclaim 8, wherein the means for generating the spray of beverage includesa whirl chamber having a central outlet opening for generating a conicalspray of beverage.
 13. The device of claim 12, wherein the whirl chamberhas a conical shape narrowing toward the central outlet opening, thecentral outlet opening being located at the lowest part of the whirlchamber.
 14. The device of claim 12, further comprising a twisterbranch, the twister branch being disposed between the inlet opening andthe whirl chamber, the twister branch having an upstream portion and adownstream portion, the upstream portion branching from the inletopening so as to enable beverage flow from the inlet opening, and thedownstream portion communicating with the whirl chamber so as to issuebeverage into the whirl chamber in directions having a tangentialcomponent with respect to the axis of the whirl chamber.
 15. The deviceof claim 14, wherein the upstream portion of the twister branch branchesin a radial manner from the inlet opening.